SU1144982A1 - Method of manufacturing optical aspherical components - Google Patents

Abstract

A METHOD FOR MAKING OPTICAL ASPHERIC DETAILS from polished spherical blanks by heating and plastic deformation, characterized in that, in order to improve the quality and reproducibility of the shape of the part, as well as to reduce the labor intensity of the process, heating is carried out to a lower annealing temperature and after hardening, plastic deformation is carried out by multiples heating up to the upper annealing temperature and cooling to a lower annealing temperature with holdings at the edges of the cycle, while the rate of heating and cooling was Em is 0.1-10 degrees / s, and their difference within the cycle is 10-100 times.

Description

This invention relates to a method of compressing optical components with a curved surface and can be used in optical glass factories.

Known methods of manufacturing are detailed with a curved surface for technical purposes by machining fl ,.

The disadvantages of the known methods of obtaining aspherical curvilinear surfaces by machining are the complexity and high cost of equipment, the multi-stage machining, fs low equipment productivity, which causes the high cost of the optical part,. Closest to the present invention, there is a method for manufacturing optical aspherical parts from polished first spherical preforms by heating and plastic deformation. According to this method, a polished spherical glass blank is placed in: a form on an air cushion. The latter is formed by passing compressed air through an opening in the mold bowl. The billet is centered and warmed up, after which the supply of compressed air is stopped and a vacuum is created in the cup, under the action of which plastic deformation of the billet takes place. The glass blank bends and adopts a configuration corresponding to the inner surface of the mold. At the end of the Molding, the workpiece is taken out of the mold 2. The disadvantages of this method are the low quality of the curved surface of the part due to contact with the form, poor reproducibility of the part geometry due to the height of the form and the laboriousness of making the forms. The purpose of the invention is to improve the quality and reproducibility of the shape of the part, and reduce the complexity of the process. This goal is achieved by the fact that, according to the method of manufacturing optical aspherical parts from polished spherical blanks, including heating and plastic deformation, heating is carried out to the lower annealing temperature and after aging a plastic deformation is performed.

by repeatedly heating to the upper annealing temperature and cooling to a lower annealing temperature with holdings at the cycle boundaries, while the heating and cooling rates are 0.1-10 degrees / second, and their difference within the cycle is 10-100 times.

The principal difference between the proposed method and the known one is that the change in the original shape is the result of the accumulation of plastic deformations caused by the relaxation of thermal stresses arising in the process of thermal cycling of the workpiece. If the heating and cooling rates differ by less than 10 times, the deviation (within measurement error), from the original form (even in the case of several hundreds of 7DIKLOV heat treatment) was not detected. If the heating and cooling rates differ by more than 100 times, the aspherization process is delayed in time and leads to a surface geometry that is not described by second order curves. I The deviation from the original shape will be the greater, the more thermal cycles are carried out, the more the heating and cooling rates differ, the wider the temperature range in the cycle is selected. As the lower limit of the thermal cycle, choose the temperature at which the rate of relaxation of thermal stresses is negligible because of the high glass. Upper cycle temperature should not exceed temperature. In which the deformation of the workpiece becomes noticeable under its own weight. in the process of thermocyclic processing, the microdefects of the machined surface of the workpiece are healed and the curved quality of the surface is ho. the finished part approaches fire-polished. In contrast to the pro. then the type of curved surface has no local. defects due to contact with the form. The complexity of the aspherization process according to the proposed method (as compared with the known ones) is significantly reduced, since it is not a problem. manufacturing laborious and expensive forms. An example. Spherical (polished in class 6) blanks of glass of the brand K-8 (diameter - 54, height 20, radius of curvature 30 mm) at. 450 ° C (LOWER annealing temperature) was held at 300 ° C to equalize the temperature difference over the workpiece. Then, the workpiece was subjected to plastic deformation by heating it to or 600 ° C (upper annealing temperature), holding at this temperature for 300 s, cooling to (lower annealing temperature), holding it, etc. The cycle was repeated from 2 to 100 times, while the rate of heating and cooling was 0.1-10 degrees / s, and their difference within the cycle 10-100 times. 824 After termination of thermal cycling, 3aroTOBky was cooled by inertia in the muffle to room temperature and measured using a set of calibrated rings with a digital indicator. As can be seen from the table characterizing the parameters of the proposed method, the obtained curvilinear surfaces are described by second-order curves with a deviation of t1 µm, while the curvilinear surface is close in quality to fire-polished. The proposed method allows organizing a continuous process of aspherization of spherical blanks in the annealing lehr, improves the quality of surface treatment, improves the reproducibility of the part geometry and reduces the complexity of the process of aspherization of optical parts.

2115

8 2

+

1365

12

+ 18

765

eight

690

690

765

four

1365

26

12 28

2115

60

10.0 -0.1 100, 0.1 10.0 100 + Note -

tically not achieved)

Table continuation

4501913

1 23

580 1913 - the obtained surfaces are not described by curves of the second order; the deviation from the initial sphere lies within the measurement error (aspherization

Claims (1)

METHOD FOR PRODUCING OPTICAL ASPHERIC DETAILS from polished spherical blanks by heating and plastic deformation, characterized in that, in order to improve the quality and reproducibility of the shape of the part, as well as to reduce the complexity of the process, the heating is carried out to a lower annealing temperature and after exposure, plastic deformation is carried out by repeated heating up to the upper temperature of annealing and cooling to the lower temperature of annealing with extracts at the cycle boundaries, while the heating and cooling rate is 0.1-10 deg / s, and their difference within the cycle is 10-100 times. (61) 1 1144982 2